x86: remove always-defined CONFIG_AS_SSSE3

CONFIG_AS_SSSE3 was introduced by commit 75aaf4c3e6a4 ("x86/raid6:
correctly check for assembler capabilities").

We raise the minimal supported binutils version from time to time.
The last bump was commit 1fb12b35e5ff ("kbuild: Raise the minimum
required binutils version to 2.21").

I confirmed the code in $(call as-instr,...) can be assembled by the
binutils 2.21 assembler and also by LLVM integrated assembler.

Remove CONFIG_AS_SSSE3, which is always defined.

I added ifdef CONFIG_X86 to lib/raid6/algos.c to avoid link errors
on non-x86 architectures.

lib/raid6/algos.c is built not only for the kernel but also for
testing the library code from userspace. I added -DCONFIG_X86 to
lib/raid6/test/Makefile to cator to this usecase.

Signed-off-by: Masahiro Yamada <[e-mail]>
Reviewed-by: Jason A. Donenfeld <[e-mail]>
Reviewed-by: Nick Desaulniers <[e-mail]>
Acked-by: Ingo Molnar <[e-mail]>

arch/x86/Makefile

···
 endif
 
 # does binutils support specific instructions?
-asinstr += $(call as-instr,pshufb %xmm0$(comma)%xmm0,-DCONFIG_AS_SSSE3=1)
 avx_instr := $(call as-instr,vxorps %ymm0$(comma)%ymm1$(comma)%ymm2,-DCONFIG_AS_AVX=1)
 avx2_instr :=$(call as-instr,vpbroadcastb %xmm0$(comma)%ymm1,-DCONFIG_AS_AVX2=1)
 avx512_instr :=$(call as-instr,vpmovm2b %k1$(comma)%zmm5,-DCONFIG_AS_AVX512=1)
···
 sha256_ni_instr :=$(call as-instr,sha256msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA256_NI=1)
 adx_instr := $(call as-instr,adox %r10$(comma)%r10,-DCONFIG_AS_ADX=1)
 
-KBUILD_AFLAGS += $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
-KBUILD_CFLAGS += $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
+KBUILD_AFLAGS += $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
+KBUILD_CFLAGS += $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
 
 KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
 

arch/x86/crypto/blake2s-core.S

···
 #endif /* CONFIG_AS_AVX512 */
 
 .text
-#ifdef CONFIG_AS_SSSE3
 SYM_FUNC_START(blake2s_compress_ssse3)
 	testq		%rdx,%rdx
 	je		.Lendofloop
···
 .Lendofloop:
 	ret
 SYM_FUNC_END(blake2s_compress_ssse3)
-#endif /* CONFIG_AS_SSSE3 */
 
 #ifdef CONFIG_AS_AVX512
 SYM_FUNC_START(blake2s_compress_avx512)

lib/raid6/algos.c

···
 EXPORT_SYMBOL_GPL(raid6_datap_recov);
 
 const struct raid6_recov_calls *const raid6_recov_algos[] = {
+#ifdef CONFIG_X86
 #ifdef CONFIG_AS_AVX512
 	&raid6_recov_avx512,
 #endif
 #ifdef CONFIG_AS_AVX2
 	&raid6_recov_avx2,
 #endif
-#ifdef CONFIG_AS_SSSE3
 	&raid6_recov_ssse3,
 #endif
 #ifdef CONFIG_S390

lib/raid6/recov_ssse3.c

···
  * Copyright (C) 2012 Intel Corporation
  */
 
-#ifdef CONFIG_AS_SSSE3
-
 #include <linux/raid/pq.h>
 #include "x86.h"
 
···
 #endif
 	.priority = 1,
 };
-
-#else
-#warning "your version of binutils lacks SSSE3 support"
-#endif

lib/raid6/test/Makefile

···
 
 ifeq ($(IS_X86),yes)
         OBJS   += mmx.o sse1.o sse2.o avx2.o recov_ssse3.o recov_avx2.o avx512.o recov_avx512.o
-        CFLAGS += $(shell echo "pshufb %xmm0, %xmm0" |		\
-                    gcc -c -x assembler - >/dev/null 2>&1 &&	\
-                    rm ./-.o && echo -DCONFIG_AS_SSSE3=1)
+        CFLAGS += -DCONFIG_X86
         CFLAGS += $(shell echo "vpbroadcastb %xmm0, %ymm1" |	\
                     gcc -c -x assembler - >/dev/null 2>&1 &&	\
                     rm ./-.o && echo -DCONFIG_AS_AVX2=1)